A large percentage of the adult population suffers from insomnia in some form at some time in their lives. This may vary from an occasional episode to chronic conditions and may involve onset and/or maintenance insomnia. Chronic insomnia is typically accepted to involve episodes greater than three (3) weeks in duration. The effects of sleep deprivation resulting from such insomnia are well known and need not be described herein other than to say that they are to be avoided.
Currently, there exist treatments only for acute insomnia. These treatments involve the administration of medication, either of the non-barbiturate or barbiturate type, shortly before bedtime. While both types of sedatives may be used to effectively treat insomnia, neither is without its undesirable side effects. For instance, barbiturate type sedatives, such as secobarbital sodium (sold by Eli Lilly and Company under the tradename of Seconal.RTM.) are general depressants. While effective, these medications are well known to lose their effectiveness after a few days. They are further highly addictive and commonly abused. They are therefore no longer widely prescribed.
The group of medications now most commonly used for the treatment of insomnia are the benzodiazepines. There are now 5 such "hypnotics" commonly used. They differ significantly in half lives but are otherwise very similar and equally effective. They have supplanted the barbiturates as the principal treatment for insomnia because they have slightly less addiction potential and are associated with less risk for suicide than the barbiturates unless taken with alcohol. However, this group, too, is know to be effective only for acute or short term insomnia and the medications are not acceptedly used for chronic insomnia. Furthermore, they are also addictive and their wide usage is drawing increasing concern as their potential side effects become more apparent. These include daytime sedation, decreased cognitive abilities such as memory loss and, most recently in the case of Halcion.RTM.(triazolam), agitated behavior.
The present invention involves the administration of very small doses of specific known psychotherapeutic agents. These agents include tricyclic compounds and a triazolopyridine derivative which are currently prescribed both for the general treatment of depression and for the treatment of the insomnia component of a depression in individuals suffering from severe depression. These compounds are known to possess a sedative effect in such individuals when administered in moderate to large dosages. However, the use of these compounds at the extremely low dosages claimed herein for the successful treatment of chronic insomnia in otherwise healthy individuals has not been reported and is not obvious in view thereof. For example, the compounds used in the present invention are currently prescribed for a 20-60 year old depressed patient population in dosages varying from about 75 to about 300 milligrams per day of the tricyclic compounds and about 150 to about 600 milligrams per day of the triazolopyridine compound. The entire dosage of such medications are often administered at bedtime. In contrast, the method of the present invention involves the use of a small fraction of such dosage.